Process of converting a fibrous material



Fatented Feb. 25, 11936 PRQCESS F CONVERTING A FIBROUS MATERIAL Richard Freudenberg, Hans Freudenberg, Roland lltunkel, and Gustav Lange, Weinheim, Germany, assignors to Carl Freudenberg G. m. b. 11.,

Weinheim (Badenia) company Germany, a German No Drawing. Application August 31, 1934, Serial No. 742,351. In Germany September 5, 1933 '3 illaims.

cal means into products, in which the fibres or fibre-bundles are in a free condition. Such products can be worked up into artificial leather, artificial gut and other products. The further working up of such fibrous material has hitherto been generally carried out in conjunction with its production.

The object of this invention is to convert fibrous materials obtained from animal skins into a dry, storable and transportable condition.

It has been found that by the usual drying methods, such as drying in the air, drying in a current of air which is heated if necessary or by other heat treatment, the conversion into useful productsds not obtained. The fibres thereby undergo undesirable changes to a more or less extensive degree, for example the fibres become horny and undesirable sticking together of the .fibres results.

It has been found according to this invention that excellent products can be obtained by washing the fibrous materials with the aid of organic liquids, miscible with water, such as alcohol, acetone and the like. If the water or the liquid contained in the fibrous material is displaced to a large extent or practically completely by said organic liquids and then the organic liquid removed, a dry storable fibre commodity with excellent characteristics is obtained.

The conversion of the skins into fibrous material can be carried out in any desired manner, for example that in which the skins are converted into fibres by chemical or physico-chemical reacting materials for example alkaline materials or acid or salt solutions producing a swelling action, or by a more complicated treatment, for example in which they are submitted to the action of alkaline materials and acids and to one or more mechanical treatments. duction of the skins to fibres can take place in a more or less swollen condition. The treatment The reof the skinswith chemicals can also take place in connection with mechanical shredding, or between the successive stages of a multi-stage mechanical treatment. Finally the chemical treatment may take place entirely or partly during the course of the mechanical treatment of the skins.

The skins, which have undergone a normal or 5 prolonged liming, may, for example, be shredded in the presence of the lime taken up during this process or after previous more or less complete removal of the same; or the limed skins can be treated if necessary by an intermediate process of washing with other chemicals, such as dilute hydrochloric acid, formic acid, acetic acid or sulphurou's acid and then shredded; or limed skins can he shredded, the shredded ma? terial treated with water or aqueous solutions such as weak acids, and then subjected to further shredding if required. If chemicals are still retained in the fibrous material they can be completely or nearly completely removed by known methods such as washing or precipitation with other chemicals and washing out the products of precipitation and the like.

Chemicals which are harmless or which are advantageous can if desired also be left in the fibrous material or only partly removed. For instance fibrous material containing acids can be partially washed with alcohol and thereby a certain acidity will be retained in the fibres.

According to this invention the fibrous mate rial obtained by the methods hereinbefore described or by any other method after separation from the main quantity of liquid present by such .methods as draining, pressing, centrifuging and the like is treated with organic liquids which are miscible with water under such conditions that the water is replaced by the organic liquid.

This can be most simply effected by allowing the organic liquid to trickle through the fibrous material or by sucking or forcing the organic liquid through the fibrous material. It is advantageous to arrange several treatment baths, charged with fibrous materials connected in series and to run the organic liquid through the system. A

When the desired amount of water has been removed, the organic liquid can be removed by known methods such as drying in the air, treatment with air which is warmed if necessary, or treatment with other gases, or by heating or similar methods. The amount of water to be removed by the organic liquid is determined by the kind and quality of the fibrous material and the nature of the proposed subsequent treatment.

In general it has been found that the less sensitive the fibrous material is to heat, the greater is the proportion of water that can be expelled. In consequence of the more thorough expulsion of water, quicker drying is achieved by the use of higher temperatures. Naturally drying can also be effected or assisted by suction and similar means. Following the resulting drying, fibrous material is obtained in the desired storable and transportable condition. It can for example be compressed into bales and thus dispatched.

According to one embodiment of the invention the fibrous material is treated with small quantities of chemicals before or during the water elimination process. One method is to add a suitable quantity of acid such as hydrochloric acid to the organic liquid miscible with water, preferably towards the end of the water expulsion process, and thus to obtain an even distribution of the acid throughout the fibrous material.

After evaporating off the organic solution the acid isretained in the fibrous material. Thus it is possible to give the fibrous material a desired acidity or pH value. An acid-containing fibrous material of this kind is especially suitable for many subsequent processes such as for the manufacture of artificial gut, leather and the like. The production of artificial gut can be carried out very simply, for example by making the fibrous material into a paste of suitable consistency by adding an appropriate amount of water and working it up into the desired state by forcing it out through nozzles and drying it.

Compounds or materials such as soluble bases, salts, fats, oxidized or non-oxidized oils, tanning agents, dyestuffs, wetting agents and the like or if desired several of these compounds, which are soluble in the organic liquid used for water expulsion, can be introduced into the fibrous material simultaneously or successively, and thus influence the properties of the fibrous material as desired. In order to obtain a solution of the substances to be added, or in order to assist their solution, other solvents or assistants can be added to the aforesaid organic solvents miscible with water.

By treating the fibrous materials with organic liquids miscible with water, to which if desired other solvents can be added, a more or less complete fat removal can be eifected.

According to another embodiment of the invention, the fibrous material obtained from skins undergoes an intermediate treatment for example tanning, and the tanned fibres can be produced in the desired dry state by the action. of organic solvents miscible with water and evaporation of the solvent. The tanning of the fibrous material can be effected by known methods such as vegetable tanning, mineral tanning and the like.

In this case also the use of organic solvents affords the advantage that undesirable influences and'changes in the fibrous material during the drying operation are avoided.

The invention has the advantage of converting skin waste into durable fibrous material, at the place where it occurs, and this can then be sent to the desired place where it is to be further worked up and stored there until required. Further the fibrous material, as already explained, can be converted by aqueous solutions into pulp, spongy or paste form and the like and in this conditionworked up into forms such as artificial gut, leather and the like.

Examples ing or similar-means. The main body of the water present or the aqueous solution present is removed by pressure, centrifuging or similar means and the water then remaining is removed by treatment with alcohol or acetone until the desired degree of removal is obtained, and the organic solvent remaining behind is then removed by evaporation. The dry fibrous material is now in a condition for storage or transport. By kneading with water or aqueous solutions it can be transformed into a pasty condition and further worked up in this form.

2. Fibrous material treated acording to Example 1 is subjected to treatment with alcohol containing hydrochloric acid after the step of eliminating water by means of alcohol, whereby after drying by evaporating oi the alcohol, the dry product retains the hydrochloric acid tenaciously and does not give it off into the air either in storage or during transport. The fibrous material containing hydrochloric acid forms a paste when kneaded with a little water, which can be worked up for desired uses.

3. 1000 kgs. of limed skin waste (hide scraps) were treated for from 8 to 14 days with milk of lime at room temperature and then shredded with ing treating the fibrous material with at least one organic liquid miscible with water so that said fibrous material is at least to a large extent freed from water, and directly thereafter drying said fibrous material.

2. A process of converting a fibrous material, obtained from a skin substance and containing water, into stable transportable fibres, comprising treating the fibrous material with at least-one organic liquid miscible with water so that said fibrous material is at least to a large extent freed from water and drying said material 'without bringing it into contact with further water.

3. A process of converting a fibrous material, obtained from a skin substance and containing water, into stable transportable fibres, comprising treating the fibrous material with a mixture of at least one organic liquid miscible with water and at least one other organic liquid so that said fibrous material is at least to'a large extent freed from water, and directly thereafter drying said fibrous material.

4. A process of converting a fibrous material, obtained from a skin substance and containing water, into stable transportable fibres, comprising treating the fibrous material with at least one organic liquid miscible with water so that said fibrous material is at least to a large extent freed from water, introducing into saidfibrous material at least one substance selected from the group consisting of acids, tanning materials, dyestufis, fats, oils and wetting agents, and directly thereafter drying said fibrous material.

5. A process of converting a fibrous material, obtained from a skin substance and containing water, into stable transportable fibres, comprisaosaias 3 ing treating the fibrous material with at least one organic liquid miscible with water so that said fibrous material is at least to a large extent freed from water, said organic liquid having dissolved therein at least one substance selected from the group consisting of acids, tanning materials, dye stuffs, fats. oils and wetting agents, and directly thereafter drying said fibrous material.

6. A process of converting a fibrous material, obtained from a skin substance and containing water, into stable transportable fibres, comprising treating the fibrous material with' a tanning agent, treating the tanned material with at least one organic liquid miscible with water so that said fibrous material is at least to a large extent freed from water, and directly thereafter drying said fibrous material.

7 Dry storable and transportable fibres of animal skin transformable into a pasty condition by kneading with water, which have been substantially freed from water by a treatment with at least one organic liquid miscible with water, immediately followed by drying.

RICHARD FREUDENBERG. HANS FREUDENBERG. ROLAND RUNKEL. GUSTAV LANGE. 

